The present invention relates to surface cleaning apparatus, and particularly to apparatus for cleaning carpets. One of the most popular types of carpet cleaners utilized today is the steam cleaner. These devices employ a carriage upon which a large clean water tank and a large recovery tank are mounted. Such devices are quite bulky and difficult to transport. Further, the clean water tank must be repeatedly filled and the dirty water tank must be repeatedly emptied. Also the distance between the suction nozzle used in conjunction with the steam cleaner and the blower or impellor which is mounted on the recovery tank causes the requirement of a very high-powered blower in order to generate enough suction to remove excess water from the carpet. The noise generated from such large blowers causes operator discomfort.
In order to place the blower in close proximity to the suction nozzle, patent application, Ser. No. 352,623, entitled SURFACE CLEANING APPARATUS, invented by Terry H. Jones and John T. Oakes, filed on Apr. 19, 1973 and patent application Ser. No. 405,819, entitled SURFACE CLEANING APPARATUS, invented by Terry H. Jones, filed on even date herewith, both assigned to the assignee of this application, show a portable sink connected surface cleaner and an improved version of the same utilizing a blower mounted in a housing in close proximity to a suction nozzle to effect a more efficient suction. This surface cleaner utilizes a small recovery tank between the suction nozzle and blower, with a shield mounted generally in front of the blower. A set of spray nozzles is mounted rearward from the suction nozzle and sprays cleaning fluid on the carpeted surface. A pump pumps the recovered used cleaning water from the recovery chamber to a remote source of discharge.
Though this surface cleaner is a great improvement over the prior art surface cleaners, many problems are associated with the cleaner. First of all, when the intermediate recovery chamber is pumped empty, the pump is dry operated causing severe wear and damage to the internal workings of the pump and to the pump motor due to overheating. Also, since the device utilizes a remote source of cleaning fluid supply such as a plumbing fixture, fluctuations in source pressure hinder efficient operation of the device. Whenever source pressure is low, additive flow into the cleaning fluid is retarded or may even stop, and whenever the source pressure is too great the recovery tank may become overfilled, and eventually will spill over the shield into the blower. Also, a constant concentration of additive in the cleaning fluid is not maintained when the source pressure fluctuates, since the additive is injected into the cleaning fluid flow due to an aspirator effect regulated by water volume through the injector. Another problem associated with the Jones device is that the housing mounted blower is loud and causes discomfort to the operator.